The role of IL-6 AND IL-17 IN pathogenesis of systemic sclerosis and evaluation to associations with clinical manifestations

Aim and Hypothesis: The pathogenesis of systemic sclerosis (SSc) remains unknown. However, what is known about this autoimmune disease is the important role of cytokines and T cell activation and auto-antibodies production leading to microvascular damage, inflammation and fibrosis. We aimed to determine the association between the serum levels of IL-6 and IL-17 which plays an important role in B and T cell activation respectively and the clinical manifestations of SSc. Methods: İn this study, 31 SSc patients, 20 ankylosing spondylitis (AS) patients and 18 healty controls included. IL-6 and IL-17 cytokines levels of all cases were identified by the ELISA methods. All cases ESR, CRP and demographic characteristics were recorded. SSc patients Anti-Scl70, anticentromere, FVC, PAB, HRCT findings and Modified Rodnan Skin Score (MRSS) values were recorded. All these data were statistically compared. Results: The serum levels of IL-6 and IL-17 were not elevated in SSc patients. Mean disease duration in SSc patients was 9,6±6,9 years. No association were found between clinical findings and levels of IL-6 and IL-17 in SSc patients. IL-17 and CRP levels in AS patients were significantly higher (p<0.05). In SSc patients, elevated ESR and MRSS high values were associated with anti-Scl70 positive (p<0.05). Conclusion: In our study that investigated role of IL-6 and IL-17 levels in the pathogenesis of SSc, no significant difference the serum levels of IL-6 and IL-17 in SSc patients compared to AS patients and healty controls. Serum IL-17 levels were significantly higher only in AS patients. In SSc patients, a relationship between the serum levels of IL-6/IL-17 and clinical findings has not been established. The reasons of these results in SSc patients are that longer disease duration and therefore it is more dominant fibrosis than inflammation. Consequently, The studies are needed to evaluate between cytokine levels and clinical findings in early stage of SSc patients. Key words: IL-6, IL-17, cytokine, systemic sclerosis